Dissociating Attention and Eye Movements in a Quantitative Analysis of Attention Allocation

Abstract

In a recent paper, we introduced a method and equation for inferring the allocation of attention on a continuous scale. The size of the stimuli, the estimated size of the fovea, and the pattern of results implied that the subjects' responses reflected shifts in covert attention rather than shifts in eye movements. This report describes an experiment that tests this implication. We measured eye movements. The monitor briefly displayed (e.g., 130 ms) two small stimuli (≈1.0 • × 1.2 • ), situated one atop another. When the stimuli were close together, as in the previous study, fixations that supported correct responses at one stimulus also supported correct responses at the other stimulus, as measured over the entire session. Yet, on any particular trial, correct responses were limited to just one stimulus. This pattern suggests that the constraints on responding within a trial were due to limits on cognitive processing, whereas the ability to respond correctly to either stimulus on different trials must have entailed shifts in attention (that were not accompanied by eye movements). In contrast, when the stimuli were far apart, fixations that had a high probability of supporting correct responses at one stimulus had a low probability of supporting correct responses at the other stimulus. Thus, conditions could be arranged so that correct responses depended on eye movements, whereas in the "standard" procedure, correct responses were independent of eye movements. The results dissociate covert and overt attention and support the claim that our procedure measures covert attention.

Behavioral psychology’s matching law describes the allocation of covert attention: A choice rule for the mind.

“…A fixed probability determined which one was the target (as in probability matching studies), and, accordingly, the participant’s task was to report on the contents of this stimulus. Although the two stimuli projected an image that did not exceed the dimensions of the fovea, (e.g., Wandell, 1995), which we confirmed in an eye-tracking study, (Heyman et al, 2017), the stimulus duration times were tailored to each participant so that he or she could report correctly on one stimulus, but not both. That is, the participants “saw” both stimuli but were able to identify the contents of just one.…”

“…The readings suggested parallels between attention allocation and choice (e.g., Corbetta, Miezin, Dobmeyer, Shulman, & Petersen, 1990;Sperling, 1960). To test this idea, we developed a mathematical model and experimental procedure for calculating the allocation of covert visual attention; eye movements played no role (Heyman et al, 2016(Heyman et al, , 2017. The results were systematic, but This document is copyrighted by the American Psychological Association or one of its allied publishers.…”

“…The current experiment builds on two earlier studies from our laboratory (Heyman, Grisanzio, & Liang, 2016; Heyman, Montemayor, & Grisanzio, 2017). In these studies, a computer monitor displayed two, small, adjacent stimuli.…”

A comparative study of Greek and Bulgarian older adults’ perceptions of their own psychological well-being and distress one year after the beginning of the Covid-19 pandemic

“…The visual world is experienced by means of eye fixations (Borys & Plechawska-Wójcik, 2017;Dolgünsoz, 2015;Heyman et al, 2017;Schneider, 2018). Fixations are essentially when our eyes stop scanning a scene, enabling us to extract detailed information from visual surroundings (Tobii Pro, 2020).…”

Modeling Task Effects in Human Reading with Neural Network-based Attention

“…In human vision, a distinction is sometimes made between overt and covert attention, where overt attention refers to the location that is behaviorally prominent a given point in time (typically the point of fixation), while covert attention refers to the current focus of cognitive processing. For example, it is possible that visual recognition occurs at a given location even though that location is not overtly attended (i.e., fixated), as Heyman, Montemayor, and Grisanzio (2017) show. Furthermore, there is evidence that viewers can classify visual scenes (i.e., perceive the gist of a scene) in the absence of overt attention (Li, VanRullen, Koch, & Perona, 2002).…”